The present invention relates network communications, especially to a network device, a network connection detector and a detection method thereof.
Due to fast development of computer technology, there is a trend for higher processing speed with lower power consumption. Especially for notebooks, less power consumption ensures longer use time. Generally, when the network devices that conform to IEEE802.3 standard, such as network cards, hubs, switches, and routers, connect with each other, information is exchanged by issuance of a link pulse. Then a suitable communication protocol is chosen to transmit information.
Referring to FIG. 1, a typical network system includes a first network device 10 and a second network device 20. The first network device 10 comprises a first control unit 12, a first transmitter 14, and a first receiver 16, and the second network device 20 comprises a second control unit 22, a second transmitter 24, and a second receiver 26. The first control unit 12 is used to control the first transmitter 14 and the first receiver 16 while the second control unit 22 is for control of the second transmitter 24 and the second receiver 26, so that information is sent from the first transmitter 14, through the local area network (LAN) or Internet, and then received by the second receiver 26. Alternatively the information is sent from the second transmitter 24, through the local area network (LAN) or Internet, and then received by the first receiver 16.
When the network connection between two corresponding network devices has not been established, the link pulse is repetitively transmitted from a first network device, while a second network device needs to constantly monitor reception of such link pulse. According to IEEE802.3 standard, the link pulse should be transmitted every 16 ms until the link pulse is received and the connection is established. Even under the condition that one of the network devices is powered off or the network cables are not connected, the link pulse is still constantly transmitted and monitored. Therefore, a lot of power is so consumed by the network devices.
There are three modes in terms of Ethernet connection speed: 10 Mbps, 100 Mbps, 1000 Mbps. The 1000M mode requires four pairs of wiring (i.e., 8 wires) for transmission while 10M/100M mode only need two pairs of wiring. Before establishing connection between two corresponding network devices, only two pairs of network wiring are used for transmission and the mode is selected by auto negotiation procedure. However, since there is no 1000M mode for network connection in early days, only network cables with two pairs of wiring are installed when building up infrastructure in home or office environment. When both of the corresponding network devices support 1000M mode, the auto negotiation procedure usually prefers the 1000M mode as a prioritized mode. However, due to the inferiority of the actual infrastructure installment (i.e., with only two pairs of wiring), which does not support network connection under 1000M mode, the issuing and monitoring of link pulses for 1000M mode will be repeated without resulting in any successful connection. Only after repeating the issuing and monitoring of the link pulse for a preset number of times or a predetermined period of time and the connection is still not established, will the network device then select modes with lower speed such as the 100M mode. Such repetitive issuing and monitoring of link pulses causes waste of time and unnecessary power consumption.
Thus there is a need to provide a novel network connection detector and a detection method thereof, which improves the shortcoming of undue power consumption caused by continuous issuing/monitoring of link pulses, and thereby saves time to establish network connection and improves quality of network connection.